Use of radiation therapy to treat tumors, and possibly other areas of targeted tissue, is widely known. There are a number of challenges associated with using radiation to treat targeted areas of tissue in a patient's body. One challenge is identifying the location of the volume of tissue in the patient's body which is targeted for treatment. Another challenge is shaping the radiation field so that the radiation field directed to the patient's body conforms to the area of tissue which is identified for treatment.
A number of different techniques can be used to control the shape of the radiation field which is directed the targeted area of the patient's tissue. One widely used device for controlling the shape of the radiation field is a multi-leaf collimator, which may be referred to at points herein as a MLC for ease of reference.
Previous MLCs have been provided in a wide range of different designs, and generally utilize a number of movable leaves which interposed in the path of radiation, to block a portion of the radiation emitted by a radiation source, and the unblocked radiation forms a radiation field shape which is then incident at an isocenter plane. One example of a prior MLC is shown in U.S. Pat. No. 5,166,531, entitled LEAF-END CONFIGURATION FOR MULTI-LEAF COLLIMATOR, which is assigned to the same assignee as the present application, and which is incorporated herein by reference. Additional aspects of other examples of MLC implementations are shown in U.S. Pat. No. 6,891,178; U.S. Pat. No. 5,012,506; and U.S. Pat. No. 6,600,810, each of which is incorporated herein by reference.
In operation a radiation treatment system using an MLC is designed to balance a number of competing factors in order to provide a combination of characteristics which will provide a tool which medical personnel can use to provide a patient with effective and efficient targeted and controlled radiation treatment.